The provision of additional operational control elements, such as control tabs installed at the trailing edge of the sternplanes on a submarine, has heretofore been considered in order to improve operational performance of the submarine with respect to sternplane jam recovery, and low and high speed maneuvering of the submarine. Such hydrodynamic control tabs are analogous to use of trim tabs on airfoils such as aircraft wings. However, use of such additional control tabs involved certain problems such as installational space requirements for the associated remote control actuator system, and generation of structural noise. The advantage in utilizing shape-memory cables made of Nitinol for size reduction of the remote control actuator system is well suited for a submarine environment because of its non-magnetic and corrosion resistance properties. Use of thermoelastic Nitinol introduces other problems because of the cooling and resetting properties of Nitinol cables. It is therefore an important object of the present invention to provide a shape-memory type of actuator system for remote control of control tabs or the like on structures such as submarines despite the problems associated therewith, without excessive expansion of required installational space or generation of electrical motor noise.